Asynchronous Programming and Concurrency Questions

Core concepts and practical patterns for writing correct and efficient asynchronous code on mobile platforms. Topics include the distinction between the main user interface thread and background threads, scheduling and prioritizing background work, asynchronous I O patterns, callback versus promise versus async await styles, structured concurrency and cancellation, concurrency primitives and thread safety, race conditions and deadlocks, synchronization and immutability strategies, reactive and stream based approaches, platform specific implementations such as coroutines and dispatch queues, best practices for testing and debugging concurrent code, and the performance and battery trade offs of different concurrency choices.